During the 140-RJ Cassini swingby of Jupiter in December
2000, the Composite Infrared Spectrometer (CIRS) acquired
global maps of Jupiter with a spatial resolution up to
2.5o of latitude at the sub-spacecraft point at
middle-infrared wavelengths (600-1400 cm-1).
Temperatures retrieved from this spectral range are in the
upper troposphere and tropopause region (50-400 mbar), and
in the middle and upper stratosphere (0.8-10 mbar). Zonally
averaged temperatures imply a mean zonal wind that does not
have a simple structure: the winds decay with altitude near
the tropopause, but higher up they can either decay to a
state of no relative motion or build up again, implying a
complex spatial distribution of momentum forcing. Zonal mean
temperatures at low latitudes exhibit an interesting
behavior. Near 100 mbar and 1 mbar, equatorial temperatures
are several kelvin cooler than those 10-15o N or S.
However, at 5-20 mbar the equatorial temperatures are ~5 K
warmer. At the tropopause, the equatorial temperature
minimum is much more pronounced than observed at the time of
Voyager. While a number of mechanisms could account for this
spatial behavior, it is likely related to the temporal
variation in the equatorial stratospheric temperatures that
have been reported from ground-based observations. The
global maps obtained show the two auroral hot spots at high
northern and southern latitudes. Curiously, these spots
appear cooler than their surroundings at the 4-mbar level,
perhaps attributable to adiabatic cooling associated with
local upwelling. The maps also show a wealth of distinct
zonal structure at other latitudes. Much of this appears
quasi-stationary, but several westward-propagating features
are seen in the stratosphere.